Spotted owl demography in the central Sierra Nevada

There has been a great deal of controversy over the status of spotted owl (Strix occidentalis) populations in western North America. Therefore, we estimated the population dynamics of a population of California spotted owls (S. o. occidentalis) in the central Sierra Nevada. We assessed reproductive status at 62 territories on 253 occasions over a 10-year period and recorded 714 captures of 210 individuals over a 14-year period. Reproduction varied temporally but did not exhibit any noticeable trends, whereas survival followed a quadratic pattern: owls experienced higher survival during the middle years of the study. Demographic parameter estimates indicate that the population declined 5.2% (SE = 2.6) per year from 1990-1999. Although conditions behind this decline may change in the future, these results suggest that management of spotted owl populations and maintaining their habitat are high conservation priorities in the central Sierra Nevada.

[1]  K. Burnham,et al.  Model selection: An integral part of inference , 1997 .

[2]  David R. Anderson,et al.  Model selection strategy in the analysis of capture-recapture data , 1995 .

[3]  P. H. Leslie.  On the use of matrices in certain population mathematics. , 1945, Biometrika.

[4]  David R. Anderson,et al.  Methods for collecting and analyzing demographic data on the northern spotted owl , 1996 .

[5]  R. Cormack.  Estimates of survival from the sighting of marked animals , 1964 .

[6]  David R. Anderson,et al.  Modeling Survival and Testing Biological Hypotheses Using Marked Animals: A Unified Approach with Case Studies , 1992 .

[7]  S. Stearns,et al.  The Evolution of Life Histories , 1992 .

[8]  David R. Anderson,et al.  AIC MODEL SELECTION IN OVERDISPERSED CAPTURE-RECAPTURE DATA' , 1994 .

[9]  B. Noon,et al.  Use, interpretation, and implications of demographic analyses of northern spotted owl populations , 1996 .

[10]  Christopher A. May,et al.  Demography of Two Mexican Spotted Owl Populations , 1999 .

[11]  David R. Anderson,et al.  CLIMATE, HABITAT QUALITY, AND FITNESS IN NORTHERN SPOTTED OWL POPULATIONS IN NORTHWESTERN CALIFORNIA , 2000 .

[12]  G. Jolly.  EXPLICIT ESTIMATES FROM CAPTURE-RECAPTURE DATA WITH BOTH DEATH AND IMMIGRATION-STOCHASTIC MODEL. , 1965, Biometrika.

[13]  K. Burnham,et al.  Program MARK: survival estimation from populations of marked animals , 1999 .

[14]  B. Noon,et al.  Habitat Relations of the California Spotted Owl , 1992 .

[15]  R. J. Gutiérrez,et al.  Habitat associations of California spotted owls in the central Sierra Nevada , 1992 .

[16]  David R. Anderson,et al.  Model selection and multimodel inference : a practical information-theoretic approach , 2003 .

[17]  R. Littell.  SAS System for Mixed Models , 1996 .

[18]  R. J. Gutiérrez,et al.  California spotted owl habitat selection in the central Sierra Nevada , 1997 .

[19]  G. Seber.  The multi-sample single recapture census , 1962 .

[20]  P. H. Leslie.  SOME FURTHER NOTES ON THE USE OF MATRICES IN POPULATION MATHEMATICS , 1948 .

[21]  H. Akaike,et al.  Information Theory and an Extension of the Maximum Likelihood Principle , 1973 .

[22]  Graeme Caughley,et al.  Analysis of vertebrate populations , 1977 .

[23]  Estimates of demographic parameters and rates of population change , 1992 .

[24]  E. Forsman.  Demography of the Northern Spotted Owl : proceedings of a workshop, Fort Collins, Colorado, December 1993 , 1996 .

[25]  Kenneth P. Burnham,et al.  ADVANCED FEATURES OF PROGRAM MARK , 2002 .

[26]  David R. Anderson,et al.  Model selection and inference : a practical information-theoretic approach , 2000 .

[27]  L. Lefkovitch.  The study of population growth in organisms grouped by stages , 1965 .